1. Field of the Invention
The invention relates to a device for handling a workpiece during a shaping process.
2. Background and Related Art
DE 42 20 796 A1 discloses a handling device for holding a forged piece during a forging process, in which a traveling mechanism carries a gripping mechanism via a sleeve, the gripping mechanism having vise-grip pincers that grasp the forged piece during the forging process. The sleeve has a hydraulic chamber, and optionally may be brought into a flexible state and a rigid state by changing the internal pressure in the hydraulic chamber via a control valve.
A further device for handling a forged piece during a forging process is known from DE 100 60 709 A1, in which an oblong gripper on its one end is mounted on a support apparatus, and on its other end has a gripping mechanism with vise-grip pincers, between whose two pincer jaws the forged part or workpiece can be held. A pincer lever on the vise-grip pincers which supports one of the pincer jaws is stationarily mounted in the longitudinal direction of the gripper, while a pincer lever supporting the other pincer jaw can be brought from an opened to a closed position by swiveling via a pincer actuating device in order to clamp the workpiece between the pincer jaws, or, conversely, can be brought from the closed to the opened position to release the workpiece. A gripping arm of the gripper is connected to the vise-grip pincers, and a block piece made of an elastically deformable material is connected to the gripping arm. On its side facing away from the gripping arm, the resilient or flexible block piece is connected to an arm region which by means of a first electromotor may be pivoted up and down, and by means of a second electromotor, raised and lowered. These motions are synchronized by a control device. The handling device may be designed as a manipulator or robot.
Due to the flexibility of the block piece, the front region of this known gripper, comprising the gripping arm, vise-grip pincers, and pincer actuating device, is flexible or pivotable with respect to the rear region comprising the arm region and the drive motors, the block piece being used as a type of articulating joint or swivel bearing. If the gripper now places a forged workpiece on a forging die of a forging hammer, and the striking tool strikes the workpiece, vibrations or impacts thus produced which are transmitted to the vise-grip pincers and gripper may become damped and absorbed in the elastic block piece, thereby relieving the load on the drives. This allows the forging process, which in practice is still carried out manually, to be automated for holding the workpiece in the forging hammer.
In this handling device known from DE 100 60 709 A1, before or after the actual shaping process in the forging hammer, in particular for moving toward or away from the forging hammer for handling the workpiece, a rigid control rod is also provided which bridges the elastic block piece and produces a rigid connection between the gripping arm and the arm region on the two mutually facing sides of the block piece. The rigid control rod has a pin that engages from below into a cavity in the gripping arm. When the rigid control rod is engaged with the gripping arm, the arm region and the gripping arm are coaxially aligned with one another along the longitudinal direction of the gripper. The intrinsic weight of the front parts, in particular the vise-grip pincers, pincer actuating device, and gripping arm, holds the rigid control rod in position and ensures an essentially horizontal fixed position of the entire gripper during transport of the grasped workpiece.
To release this fixed position, when the workpiece is placed on the forging die of the forging hammer the rear arm region is lifted upward, so that it is oriented at an angle to the longitudinal direction of the front gripper region having the vise-grip pincers, and the block piece is correspondingly deformed or bent. The fixation of the rigid control rod to the gripping arm is thereby released, since the pin is swiveled out of the cavity and the rigid control rod then is no longer connected to the front gripping arm. When the rigid control rod is released, on account of its flexibility the block piece can then carry out its function as a damping element for the impacts and vibrations. To rigidly reposition the gripper, the rear arm region is simply lowered down again into a coaxial position with respect to the front arm, and the rigid control rod is again fixed to the front gripping arm by reengaging the pin in the cavity.
The motion of this known robotic handling system according to DE 100 60 709 A1 is composed of essentially a horizontal and a vertical motion produced by the second electromotor. The swivel motion produced by the first motor before the actual forging process when the workpiece is laid out serves only to release or fix the rigid control rod. The workpiece is thus constantly held in a position in which its upper and lower sides always extend horizontally, and undergoes only horizontal or vertical translatory motion. Rotation of the workpiece is not described.